Re: [PATCH net-next V2 11/11] net/mlx5e: Support ethtool tcp-data-split settings

Jakub Kicinski
2025-05-27T16:10:25Z

On Thu, 22 May 2025 16:19:28 -0700 Saeed Mahameed wrote:
> >Why are you modifying wanted_features? wanted_features is what
> >*user space* wanted! You should probably operate on hw_features ?
> >Tho, may be cleaner to return an error and an extack if the user
> >tries to set HDS and GRO to conflicting values.
> >
>
> hw_features is hw capabilities, it doesn't mean on/off.. so no we can't
> rely on that.
>
> To enable TCP_DATA_SPLIT we tie it to GRO_HW, so we enable GRO_HW when
> TCP_DATA_SPLIT is set to on and vise-versa. I agree not the cleanest..
> But it is good for user-visibility as you would see both ON if you query
> from user, which is the actual state. This is the only way to set HW_GRO
> to on by driver and not lose previous state when we turn the other bit
> on/off.

features = on
hw_features = off

is how we indicate the feature is "on [fixed]"
Tho, I'm not sure how much precedent there is for making things fixed
at runtime.